Penicillin salt of n, n&#39;-bis-p, p&#39;-carbodiethylaminoethoxyphenyl urea



Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE PENICILLIN SALT OFN,N-BIS-D,D'-CARBO- DIETHYLAMINOETHOXYPHENYL UREA Ralph N. Lulek,Rosebank, N. Y., and William M. Ziegler, Clementon, N. J., assignors, bymesne assignments, to American Cyanamid Company, New York, N. Y., acorporation of Maine No Drawing. Application January 16, 1951, SerialNo. 206,310

1 Claim.

This invention relates to new chemical compounds and to improvedprocesses by which they may be prepared. More particularly, it is cOncerned with the penicillin salts of procaine urea and to methods used inthe preparation of these 5 antibiotics.

The compounds forming the subject matter of whereby one of the compoundsrepresented by the above formula, the benzyl penicillin salt (penicillinG) of procaine urea, can be prepared, consists of a metathesis reactionbetween the potassium salt of benzyl penicillin and an acid salt ofN,N'-bis-p,p'-carbodiethylaminoethoxyphenyl urea. This reaction isindicated graphically as follows:

the present invention may be represented by the following structuralformula:

i to be within the purview of this invention.

It has now been discovered, in accordance with the present invention,that one effective method An alternative method for preparing the aboveindicated compound involves reacting the acidified benzyl penicillinsalt with N,N'--bis-p,p'- carbodiethylaminoethoxyphenyl urea. Thisreaction is indicated graphically as follows:

N,N-bis-p,p'-carboriiotl1ylaminoethoxyphenyl urea (benzyl penicillinsalt or procaine urea) N,N' bis p,p' carbodiethylaminoethoxyphenyl urea,together with a method for its preparation, are disclosed and claimed ina co-pending application of one of the present applicants, R. N. Lulek,Seria1 No. 64,241, filed December 8,

1948, and which issued as U. S. Patent No.

2,539,848 on January 30, 1951.

Regarded in certain of its broader aspects, the

novel features in the present invention comprise the preparation ofpenicillin salts of N,N'-bisp,p'-carbodiethylaminoethoxyphenyl urea bydirectly reacting a penicillin salt with an acid salt ofN,N'-bis-p,p'-car'bodiethylaminoethoxyphenyl urea, or in a modificationthereof, by reacting an acidified penicillin salt withN,N'-bis-p,p'-carbodiethylaminoethoxyphenyl urea, then extracting thepenicillin salt thus formed by the use of an: appropriate waterimmiscible organic solvent,

concentrating the solvent portion containing the antibiotic, and thenrecovering and washing the penicillin salt With a suitable solvent. Theyield obtained is quantitative, the product being a White solid, insubstantially pure form.

The dry stable salts thus produced had a melt-- f ing point rangingbetween 68-75 C. and assayed chemically (using a standard method) about800 u./mg. A bio-assay of this material, using S.

, aureus in a cylinder plate method, was about 1,000 u./mg. Theaforementioned new and novel salts of penicillin possess theantibacterial activity characteristic of penicillin salts and likewiseare quite suitable for therapeutic uses. The results of the bio-assayindicate the purity of these salts and their suitability in thepreparation of various formulations such as, a suspension of the salt ina menstruum of either peanut oil or sesame oil for prolonged bloodlevels, or an aqueous suspension useful for parenteral injections.

These penicillin salts can likewise be prepared in other forms such as,tablets, troches, etc.

In a more specific embodiment of this invention, an aqueous solution ofa penicillinsalt such as sodium or potassium benzyl penicillin, isreacted with an inorganic .acid salt .of N,'N'-" bis p,p'carbodiethylaminoethoxyphenyl =urea thereby producing by a metathesisreaction, the benzyl penicillin salt ofN,N-bis-"p,p'-carbodiethylaminoethoxyphenyl urea. Inorganic acid saltswhich have been found to be suitable in this chloroform-solutionseparating out shortly thereafter. The aqueous portion was furtherextracted with -50 cc. -.of chloroform. and the combined chloroformsolutions were dried over magnesium sulfate. :50;g rams ofN,N-bisp,p-carbodiethylreaction include the hydrochloride, sulfate,phosphate, etc.

A modification of this process comprises acidifying .a solution of thepenicillin salt with a concentrated inorganic acid such as hydrochloric,sulfuric, or phosphoric acid, and then reacting the acidified penicillinsalt with N;N'-bis-D;D'- carbodiethylaminoethoxyphenyl urea to obtainthe desiredproduct.

The penicillin salt thus formed is separated from the reaction mixtureby the use of an appropriate water immiscible organic solvent. Solventswhich havebeen found to be highly satisfactory in this extraction stepinclude chloroform, amyl acetate, methyl amyl acetate, methyl isobutylketone, etc. Since, however, excellent results are obtained whenchloroform is employed, the use of this solvent is preferred.

It should be mentioned that the solvent should also be relatively inertto penicillin; that is, should not either destroy or adversely affectthe antibiotic activity of this drug.

Since various penicillin salts ofN,N'-bis-p,pcarbodiethylaminoethoxyphenyl urea are soluble in thewater-containing organic solvent and likewise are soluble in the driedsolvent, the conventional methods of concentrating athese penicillinsalts :are ineffectual when used to isolate the desired product.Instead, the solution is dried over anhydrous salt, concentrated, andthen precipitated by the addition of ether. The salt is further washedwith a solvent such as ether or li-groin and then dried over sulfuricacid or any other suitable dehydrating agent. The final product isrecovered in substantially pure white powdery form. As in the case ofother penicillin salts, i. e. sodium .or potassium benzyl penicillin, itis essential that this salt be converted to the dry powdered form assoon as possible "because of the instability of the penicillin saltsgenerally, in any solution containing water.

Because of the sensitivity of the penicillin molecule, especially instrongly acidic and strong- 1y alkaline solutions, the reaction and thesteps in the process generally must be conducted at a low temperature,i. e. at temperatures varying between 0 to 35 0., with a preferredtempera ture range between to C., to prevent any degradatien :of theantibiotic with attendant loss of antibiotic activity. Thus, externalcooling means are used to cool the solution when the temperature risesbeyond the limits specified above.

.aminoethoxyphenyl .urea were then dissolved in this dry chloroformsolution of acid penicillin and the volume of the resulting solution wasreduced to 155 cc. by evaporation under reduced temperature at a bathtemperature of C.

300 cc. of ether was added to the syrup thus formed and the resultingmass was thoroughly mixed. The solvent was decanted from the semisolidmass and then another .300 cc. portion of ether was added thereto. Thiswas triturated until a suspension of solid occurred. The resultingsuspension was chilled over night. The material was then recovered byfiltration and dried under vacuum .over sulfuric acid. The yield wasquantitative. The resulting material assayed chemically about800'u./mg., using the standard titrimetric method. The material is awhite solid that swells and decomposes at about 75 C.

Example II 78 grams of potassium penicillin G was dis solved in 500cc.-of water and then 58 grams of l\T,N-bis p,p'carbodiethylaminoethoxyphenyl urea hydrochloride dissolved in 500 cc. ofwater were added thereto, the mixture being stirred vigorously. The'oilwas separated from the solution and then the aqueous portion of thissolumixed. The solvent was decanted from the semisolid mass and thenanother 300 cc. portion of ether was added thereto. until a suspensionof solid occurred. The suspension was chilled over night. The materialwas then removed by filtration and dried under vacuum over sulfuricacid. The yield was quantitative. The resulting material assayedchemically about 800 u./mg., using the standard .titrimetric method.

While the foregoing examples and description have been directed to thepreparation of a procaine .urea penicillin compound wherein thepenicillincomponent is identified as penicillin G, as indicated suprathe invention .is not restricted to this type of penicillin, as otherpenicillin pro caine urea compounds are also considered :to be withinthe purview of this invention.

Various changes :and modifications of the invention as described abovemay be made which This was triturated 5 6 ingly, such changes andmodifications, to the ex- We claim: tent that they are within thepurview of the I appended claim, are to be regarded as part of A newchemical compound havmg the for the invention. mulal t C: /H HN--O)c-coocmom-t: E CH:

o-o ococ--cm 1!: 1 cmom N\ 0=c 0 H H I 00 H NH-co-omo C-H 5 H H Iii IIICHICK! c=0\ H H-N-c 0-0 0 o CHaOHa-N 0H.

( v-4 OCOC-CCH: H H CHzCH: N\

0=o c E H I l o c=c H NH-COCHr-O 0-4:

W H H RALPH N. LULEK. WILLIAM M. ZIEGLER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,515,898 Rhodehamel July 18, 1950

